Process modeling and optimization for biomass steam-gasification employing response surface methodology

Abstract

This paper presents a process modeling and optimization study about steam-gasification of biomass. The gasification model is developed using Aspen Plus process simulation tool, and rice husk is considered as biomass fuel. Simulation results were validated with reported experimental results. The effects of the critical parameters, namely, steam-to-biomass ratio (S/B) and gasification temperature on the quality of the product gas as well as the gasifier cold-gas efficiency were analyzed. Response surface methodology (RSM) is employed to understand the synchronized effects of the critical decision parameters and thus to determine the optimized zone of operating condition. The study reveals that steam gasification can yield relatively clean, H2-rich (up to 58%, dry basis) product gas and the RSM analysis suggests that optimum performance is obtained for gasification temperature in the range of 750–900 °C and S/B in the range of 0.70–0.81, when the cold gas efficiency (CGE) approaches 90% and yields dry gas LHV of 12 MJ/kg and more.